Abstract
The increasing prevalence of obesity is presenting a critical challenge to healthcare services. We examined the effect of Body Mass Index in early pregnancy on adverse pregnancy outcome. We performed a population register-based cohort study using data from the North Western Perinatal survey (N = 99,403 babies born during 2004–2006), based at The University of Manchester, UK. The main outcome measures were Caesarean section delivery, preterm birth, neonatal death, stillbirth, Macrosomia, small for gestational age and large for gestational age. The risk of preterm birth was reduced by almost 10% in overweight (RR = 0.89, [95% CI: 0.83, 0.95]) and obese women (RR = 0.90, [95% CI: 0.84, 0.97]) and was increased in underweight women (RR = 1.33, [95% CI: 1.16, 1.53]). Overweight (RR = 1.17, [95% CI: 1.09, 1.25]), obese (RR = 1.35, [95% CI: 1.25, 1.45]) and morbidly obese (RR = 1.24, [95% CI: 1.02, 1.52]) women had an elevated risk of post-term birth compared to normal women. The risk of fetal macrosomia and operative delivery increased with BMI such that morbidly obese women were at greatest risk of both (RR of macrosomia = 4.78 [95% CI: 3.86, 5.92] and RR of Caesarean section = 1.66 [95% CI: 1.61, 1.71] and a RR of emergency Caesarean section = 1.59 [95% CI: 1.45, 1.75]). Excessive leanness and obesity are associated with different adverse pregnancy outcomes with major maternal and fetal complications. Overweight and obese women have a higher risk of macrosomia and Caesarean delivery and lower risk of preterm delivery. The mechanism underlying this association is unclear and is worthy of further investigation.
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References
WHO. Obesity: preventing and managing the global epidemic. Geneva: WHO publications; 2000.
Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM. Prevalence of overweight and obesity in the United States, 1999–2004. JAMA. 2006;295(13):1549–55.
Marriot H, Buttriss J. Key points from the findings of volume 4 of the National Diet and Nutrition Survey (NDNS) of adults aged 19–64 years. Nutr Bull. 2004; 29(3):249–253.
Kanagalingam MG, Forouhi NG, Greer IA, Sattar N. Changes in booking body mass index over a decade: retrospective analysis from a Glasgow Maternity Hospital. Bjog. 2005;112(10):1431–3.
Lu GC, Rouse DJ, DuBard M, Cliver S, Kimberlin D, Hauth JC. The effect of the increasing prevalence of maternal obesity on perinatal morbidity. Am J Obstet Gynecol. 2001;185(4):845–9.
Sebire NJ, Jolly M, Harris JP, Wadsworth J, Joffe M, Beard RW, et al. Maternal obesity and pregnancy outcome: a study of 287, 213 pregnancies in London. Int J Obes Relat Metab Disord. 2001;25(8):1175–82.
Cedergren MI. Maternal morbid obesity and the risk of adverse pregnancy outcome. Obstet Gynecol. 2004;103(2):219–24.
Chu SY, Bachman DJ, Callaghan WM, Whitlock EP, Dietz PM, Berg CJ, et al. Association between obesity during pregnancy and increased use of health care. N Engl J Med. 2008;358(14):1444–53.
Watkins ML, Botto LD. Maternal prepregnancy weight and congenital heart defects in offspring. Epidemiology. 2001;12(4):439–46.
Cnattingius S, Bergstrom R, Lipworth L, Kramer MS. Prepregnancy weight and the risk of adverse pregnancy outcomes. N Engl J Med. 1998;338(3):147–52.
Wilcox MA, Johnson IR, Maynard PV, Smith SJ, Chilvers CE. The individualised birthweight ratio: a more logical outcome measure of pregnancy than birthweight alone. Br J Obstet Gynaecol. 1993;100(4):342–7.
Robbins AS, Chao SY, Fonseca VP. What’s the relative risk? A method to directly estimate risk ratios in cohort studies of common outcomes. Ann Epidemiol. 2002;12(7):452–4.
The English Indices of Deprivation (revised). Office of the Deputy Prime Minister, 2004. http://www.communities.gov.uk/documents/communities/pdf/131209.pdf. Last Accessed on 23/06/2009.
O ffice for National Statistics, Postcode Directories [computer file]. ESRC Census Programme, Census Dissemination Unit, Mimas (University of Manchester), downaloded via GeoConvert: http://geoconvert.mimas.ac.uk/.
Little RE, Weinberg CR. Risk factors for antepartum and intrapartum stillbirth. Am J Epidemiol. 1993;137(11):1177–89.
Stephansson O, Dickman PW, Johansson A, Cnattingius S. Maternal weight, pregnancy weight gain, and the risk of antepartum stillbirth. Am J Obstet Gynecol. 2001;184(3):463–9.
Edwards LE, Dickes WF, Alton IR, Hakanson EY. Pregnancy in the massively obese: course, outcome, and obesity prognosis of the infant. Am J Obstet Gynecol. 1978;131(5):479–83.
Galtier-Dereure F, Boegner C, Bringer J. Obesity and pregnancy: complications and cost. Am J Clin Nutr. 2000;71(5 Suppl):1242S–8S.
Gross T, Sokol RJ, King KC. Obesity in pregnancy: risks and outcome. Obstet Gynecol. 1980;56(4):446–50.
Johnson SR, Kolberg BH, Varner MW, Railsback LD. Maternal obesity and pregnancy. Surg Gynecol Obstet. 1987;164(5):431–7.
Perlow JH, Morgan MA, Montgomery D, Towers CV, Porto M. Perinatal outcome in pregnancy complicated by massive obesity. Am J Obstet Gynecol. 1992;167(4 Pt 1):958–62.
Spellacy WN, Miller S, Winegar A, Peterson PQ. Macrosomia—maternal characteristics and infant complications. Obstet Gynecol. 1985;66(2):158–61.
Garbaciak JA Jr, Richter M, Miller S, Barton JJ. Maternal weight and pregnancy complications. Am J Obstet Gynecol. 1985;152(2):238–45.
Naeye RL. Maternal body weight and pregnancy outcome. Am J Clin Nutr. 1990;52(2):273–9.
Baeten JM, Bukusi EA, Lambe M. Pregnancy complications and outcomes among overweight and obese nulliparous women. Am J Public Health. 2001;91(3):436–40.
Crane SS, Wojtowycz MA, Dye TD, Aubry RH, Artal R. Association between pre-pregnancy obesity and the risk of cesarean delivery. Obstet Gynecol. 1997;89(2):213–6.
Kaiser PS, Kirby RS. Obesity as a risk factor for cesarean in a low-risk population. Obstet Gynecol. 2001;97(1):39–43.
Sheiner E, Levy A, Menes TS, Silverberg D, Katz M, Mazor M. Maternal obesity as an independent risk factor for caesarean delivery. Paediatr Perinat Epidemiol. 2004;18(3):196–201.
Young TK, Woodmansee B. Factors that are associated with cesarean delivery in a large private practice: the importance of prepregnancy body mass index and weight gain. Am J Obstet Gynecol. 2002;187(2):312–8. discussion 318–320.
Witter FR, Caulfield LE, Stoltzfus RJ. Influence of maternal anthropometric status and birth weight on the risk of cesarean delivery. Obstet Gynecol. 1995;85(6):947–51.
Weiss JL, Malone FD, Emig D, Ball RH, Nyberg DA, Comstock CH, et al. Obesity, obstetric complications and cesarean delivery rate—a population-based screening study. Am J Obstet Gynecol. 2004;190(4):1091–7.
Perlow JH, Morgan MA. Massive maternal obesity and perioperative cesarean morbidity. Am J Obstet Gynecol. 1994;170(2):560–5.
Acknowledgments
The authors would like to thank Ms Cathie Forest from the North Western Perinatal Survey (University of Manchester) directed by Professor Philip Baker for their assistance in providing the data. Funding: This study was funded by Tommy’s the Baby Charity and the Heath Research Board, Ireland.
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Khashan, A.S., Kenny, L.C. The effects of maternal body mass index on pregnancy outcome. Eur J Epidemiol 24, 697–705 (2009). https://doi.org/10.1007/s10654-009-9375-2
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DOI: https://doi.org/10.1007/s10654-009-9375-2